This application relates to apparatus for humidifying a gaseous stream such as air or oxygen, more particularly, relates to apparatus for admixture of water vapor into such a stream, particularly for use in medical applications such as anesthesia, inhalation therapy, and neonatal and pediatric service.
Medical application humidifiers which provide warm humidified breathing gas have been developed for pressure-cycled and volume-controlled patient ventilators as well as for continuous flow operation, such as the Vapor-Phase instruments commercially available from Intertech Resources, Inc. These humidifier instruments employ a heating element to heat a water supply which generates water vapor thereafter passed through a vapor permeable membrane into a separate ventilation stream of air or oxygen directed through the instrument for delivery to the patient.
Conventionally, the gaseous stream is directed through a reservoir chamber disposed above the heating element which drives the water vapor through the membrane upwardly into the gaseous stream passing above through the chamber. While such instruments have proved successful, a recurring tendency for vapor condensation to accumulate in the upper chamber occasionally result in water droplets entrained in gaseous stream which can later settle to form an obstruction downstream from the humidifier instrument. Furthermore, there has been no on-line provision for drainage of the condensate. Additionally, the water supply inlet in the base structure delivers the water to a check valve which controls the passage into contact with the heating element, and the check valve itself represents a water leakage hazard in proximity to the electrical circuitry which powers the heating element.
These disadvantages are eliminated by the the improved humidifier apparatus according to the present invention.